Skip to main content
Entomology 2025 Main banner
Icon Legend
This session is not in your schedule.
This session is in your schedule. Click again to remove it.
 
Oral Presentation
Oral Presentation
Poster Display
Poster Display
Student Competition
Student Competition
Ticketed Event
Ticketed Event

Poster Display

Plant-Insect Ecosystems

Poster: P-IE, Field Crops IPM

Influence of pistachio hull degradation on navel orangeworm egg deposition

Tuesday, November 11, 2025
9:00 AM - 5:00 PM Pacific
Location: Exhibit Hall A-A1, OCC
Poster Display
The navel orangeworm (Amyelois transitella) (NOW) is a key pest of pistachios, laying eggs on the nuts. The larvae develop inside the kernel, which negatively impacts yield and quality. The larvae infest the kernel when the hull/shell starts to degrade, usually later in the growing season. NOW females likely notice these changes and lay more eggs on the damaged nuts. This study aims to understand the changes in texture and chemical composition associated with hull degradation and how the NOW responds to these changes. The study was conducted in West Fresno County over two years, utilizing the Golden Hills and Kerman varieties. Insect-exclusion cages were placed over 60 clusters in each block. Five mated navel orangeworm (NOW) females were inoculated in 10 caged clusters in each block for one week. Afterward, the cages were removed to assess egg deposition on all plant parts. Data were collected from July to October for both years. Before inoculation, nuts were removed from each cluster for textural and chemical analyses, with samples taken during both day and night. In both years of the study, egg deposition on Golden Hills pistachio nuts increased over time. In contrast, no significant increase was observed in the Kerman variety. Golden Hills had a slightly lower hull texture, with notable differences on various sample dates. Pistachio hull volatiles revealed that compounds such as α-pinene, linalool, and citral were affected by variety and sampling time. In conclusion, egg deposition by female NOW moths on Golden Hills pistachio nuts increased over time, highlighting the importance of understanding hull degradation in pest management strategies.